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To achieve low standby power in a Switched-Mode Power Supply (SMPS), the goal is to reduce the power consumption when the device is in its idle or standby state. Here are some key methods used to achieve low standby power in SMPS:
1. Use of Low Power Control Circuits
- PWM (Pulse Width Modulation) Control: In standby mode, you can reduce the switching frequency and the duty cycle of the PWM controller. This lowers the power drawn by the control circuitry.
- Quiescent Current Reduction: Using low quiescent current (Iq) controllers ensures that the SMPS draws minimal current when it's not actively powering a load.
2. Standby Mode for Power Management
- Energy-efficient Standby Modes: Modern SMPS designs include dedicated low-power modes, where the system can switch to a low-power state when the load is very low or during periods of no load. In this mode, the output voltage might still be regulated, but the power conversion efficiency is improved to reduce power consumption.
- Load Sensing: Some designs detect when the load is light or zero and adjust the operating mode accordingly, effectively reducing power usage.
3. Use of External Components
- Low Power MOSFETs and Diodes: The use of MOSFETs with lower gate capacitance and low Rds(on) resistance, as well as Schottky diodes or other low-loss diodes, reduces losses during standby.
- Efficient Transformers: In SMPS, transformers with low core loss and high efficiency help minimize energy wasted during idle periods.
4. Using Integrated Circuit (IC) Solutions
- Integrated Low Standby Power Controllers: Many modern controllers are designed with low standby power consumption in mind. These controllers may use features like burst mode, which reduces the switching frequency to very low levels when the load is low.
- Power Factor Correction (PFC) Circuits: In some SMPS designs, PFC can be optimized for low power operation to ensure that the system doesn't draw unnecessary power from the grid during idle or standby conditions.
5. Passive Loss Reduction
- Minimizing Losses in Passive Components: Components like inductors, capacitors, and transformers should be chosen to have minimal losses during standby operation. This reduces the overall standby power consumption.
6. Standby Power Detection
- Low Power Detection Circuits: In some designs, the system monitors if there's any load. If no load is detected, the power supply can enter an ultra-low power standby mode where it only consumes a tiny fraction of the power it would under normal operation.
7. Zero-Voltage Switching (ZVS) or Zero-Current Switching (ZCS)
- These techniques allow the SMPS to switch at times when the voltage or current is near zero, reducing the switching losses that can occur at higher switching frequencies. This can be especially useful in standby modes to reduce overall losses.
By incorporating these methods, an SMPS can achieve very low standby power, which is essential for energy efficiency, especially in applications like power adapters, chargers, and consumer electronics that remain plugged in but are not in active use.
1. Use of Low Power Control Circuits
- PWM (Pulse Width Modulation) Control: In standby mode, you can reduce the switching frequency and the duty cycle of the PWM controller. This lowers the power drawn by the control circuitry.- Quiescent Current Reduction: Using low quiescent current (Iq) controllers ensures that the SMPS draws minimal current when it's not actively powering a load.
2. Standby Mode for Power Management
- Energy-efficient Standby Modes: Modern SMPS designs include dedicated low-power modes, where the system can switch to a low-power state when the load is very low or during periods of no load. In this mode, the output voltage might still be regulated, but the power conversion efficiency is improved to reduce power consumption.- Load Sensing: Some designs detect when the load is light or zero and adjust the operating mode accordingly, effectively reducing power usage.
3. Use of External Components
- Low Power MOSFETs and Diodes: The use of MOSFETs with lower gate capacitance and low Rds(on) resistance, as well as Schottky diodes or other low-loss diodes, reduces losses during standby.- Efficient Transformers: In SMPS, transformers with low core loss and high efficiency help minimize energy wasted during idle periods.
4. Using Integrated Circuit (IC) Solutions
- Integrated Low Standby Power Controllers: Many modern controllers are designed with low standby power consumption in mind. These controllers may use features like burst mode, which reduces the switching frequency to very low levels when the load is low.- Power Factor Correction (PFC) Circuits: In some SMPS designs, PFC can be optimized for low power operation to ensure that the system doesn't draw unnecessary power from the grid during idle or standby conditions.
5. Passive Loss Reduction
- Minimizing Losses in Passive Components: Components like inductors, capacitors, and transformers should be chosen to have minimal losses during standby operation. This reduces the overall standby power consumption.6. Standby Power Detection
- Low Power Detection Circuits: In some designs, the system monitors if there's any load. If no load is detected, the power supply can enter an ultra-low power standby mode where it only consumes a tiny fraction of the power it would under normal operation.7. Zero-Voltage Switching (ZVS) or Zero-Current Switching (ZCS)
- These techniques allow the SMPS to switch at times when the voltage or current is near zero, reducing the switching losses that can occur at higher switching frequencies. This can be especially useful in standby modes to reduce overall losses.By incorporating these methods, an SMPS can achieve very low standby power, which is essential for energy efficiency, especially in applications like power adapters, chargers, and consumer electronics that remain plugged in but are not in active use.